Who was the 3rd professional, who lost to Fernando Aguilar?

Fernando Aguilar from Argentina is famous for beating two Japanese 9-dans.
He also beat few professionals online. Here is an example.
His opponent is "daya", currently 8-dan on IGS, ranking #6 in IGS best 100 list
Daya has 1081W-604L score.
I don't know his real name, but I heard that he is Japanese professional.
He tried to kill Fernando and ... got killed himself